This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application.
In wireless communication, different collections of communication protocols are available to provide different types of services and capabilities. The long term evolution (LTE) is one of such collection of wireless communication protocols that extends and improves the performance of existing UMTS (universal mobile telecommunications system) protocols and is specified by different releases of the standard by the 3rd generation partnership project (3GPP) in the area of mobile network technology.
Of interest herein are the further releases of 3GPP LTE targeted towards future international mobile telephony-advanced (IMT-A) systems, referred to herein for convenience simply as LTE-Advanced (LTE-A). A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LTE-A is directed toward extending and optimizing the current 3GPP LTE radio access technologies to provide higher data rates at very low cost. LTE-A will be a more optimized radio system fulfilling the international telecommunication union radiocommunication sector (ITU-R) requirements for IMT-A while maintaining backward compatibility with the current LTE release.
Both time-division duplexing (TDD) and frequency-division duplexing (FDD) schemes are adopted in LTE. In LTE TDD scheme, the downlink (DL) transmission (from the network to the user equipment) and the uplink (UL) transmission (from the user equipment to the network) are operated at same carrier frequency, but allocated different time portion, or the so-called subframes. In LTE-A, several UL/DL subframe configurations are available for semistatic selection according to the ratio of UL and DL data. Recently, dynamic allocation of subframes to UL or DL is considered.
The concept of heterogeneous network has attracted considerable attention to optimize performance particularly for unequal user or traffic distribution. In a heterogeneous network, different layers of cells are deployed in a less well planed or even uncoordinatedly manner. To combat with the challenge of interference management, different enhanced inter-cell interference coordination (eICIC) technologies are studied, one of which is the time domain (TDM) eICIC. In TDM eICIC, almost blank subframes (ABS) are used to manage interference in DL, thus creating variable interference pattern at the receiver.